T'way Airlines

Foundation as Hansung Airlines

Trinity Airways' predecessor, Hansung Airlines, first obtained an air operator's certificate (AOC) in April 2005 and received its first aircraft, an ATR 72 for its inaugural domestic services between Cheongju and Jeju shortly after. Hansung Airlines had planned to expand to international routes and subsequently ordered 20 ATR 72-500 aircraft. However, due to financial difficulties, Hansung Airlines ceased operations in 2009.

Relaunching as T'way Air

Hansung Airlines was reorganized and rebranded in 2010 after its shutdown. The 't' in T'way stands for together, today and tomorrow. The airline was established on 8 August 2010 with two Boeing 737-800 aircraft. The following month, the airline obtained a new air operator's certificate permitting domestic operations and commenced scheduled flights between Gimpo International Airport and Jeju International Airport.

In 2011, an additional AOC for international operations was granted. In October of the same year, T'way launched its first international service, to Bangkok. In 2013, the airline achieved a profit for the first time. In November that year, cargo services were launched.

As of 2019, it was the third largest Korean low-cost carrier in the international market, having carried 2.9 million domestic passengers and 4.2 million international passengers the year prior. Its international traffic had quadrupled in the three years leading up to 2019.

In April 2022, T'way received its first Airbus A330. In October 2022, T'way announced a route from Seoul to Sydney, which is its first long-haul connection. In October 2024, the airline inaugurated flights to Germany with a route between Seoul and Frankfurt, which it had been granted due to a concession deal as part of the merger between Korean Air and Asiana Airlines, which both serve Frankfurt. In the same month, the airline announced it plans to lease Boeing 777-300ER aircraft to facilitate its expansion plans until the delivery of its new Airbus A330neos.

Rebranding as Trinity Airways

The airline officially announced its rebrand to Trinity Airways on 8 September 2025, after being acquired by Daemyung Sono Group, with a change in livery. Daemyung Sono Group subsequently rebranded as Sono Trinity Group in May 2026. The new livery will consist of large billboard titles on the front of the aircraft with a grey stripe running on the underbelly. The tail has a grey background with a triangle consisting of three colors: pink, yellow, and blue. The full rebranding is expected begin in the second half of 2026. The name change received shareholder approval in March 2026 and will be actioned subject to receiving regulatory approval.

On 4 September 2026, T'way Air changed its callsign from TEEWAY to SONOROUS, in preparation for the official rebranding of the airline. On 10 September 2026, T'way Air ceased its branding and began to operate under Trinity Airways, after completing all merger procedures between T'way Air and Daemyung Sono Group. The first flight as Trinity Airways took place on the same day between Daegu and Jeju.